Today the news that the UK’s National Sperm Bank, set up a year ago, has only nine donors so far, and is about to unveil a promotional campaign to ramp-up the volume of in-flows.

I can’t wait.

On the surface, it seems a straightforward problem to solve. But read on…

Turns out the sperm bank needs ‘super-sperm’ not just ordinary, run-of-the-mill, 33-Acacia-Avenue sperm. This is because it needs to survive the constant freezing and unfreezing process inherent in the final customer service procedure (giving infertility sufferers the chance of a child).

Out of 100 potential donor applicants, only ten survive the screening process and only 1 of those 10 will actually become a donor.

The lucky participant must attend the clinic twice a week for four months and, in exchange for £70 a session, abstain from ejaculating for two days before each visit, which essentially ensures an entirely monogamous relationship with the clinic, for the duration of the programme.

And that’s before you get to the customer selection process. People in the market for sperm tend to be quite choosy, apparently. They want donors of 6’ or more, for instance, which rules out 90% of potential UK donors straight away. And they all want doctors or barristers – most of whom are too busy, too rich, or both, to sign up.

So perhaps it’s not surprising that most donated sperm in the UK currently comes from Denmark and USA.

The forthcoming advertising campaign will ape a successful precedent in Denmark, in which men are challenged to prove their manliness by demonstrating the ‘vigour’ of their ‘guys’. A follow-up planned for Christmas is going to ask men to consider giving “an alternative Christmas gift”.

I’ll be delighted if either of these approaches works. But I wonder if they’ve learned as fully as they might, the lessons behavioural economics might teach.

In one sense it’s a bit like the Royal Marines campaign, which broadcasts the fact that 99% need not apply. “We’re only for the hardest nuts,” they say.

But the sperm-bank version would have to be – surely – “Have you got the ballsiest, bounciest swimmers in the business? (And are you also over 6’, handsome, intelligent, well adjusted and gainfully employed in a respected professional occupation). If so come and subject yourself to our test and win yourself the prize of wanking into a test-tube for four months in exchange for not much money and the eternal admiration of all your friends – who you’ll definitely tell straight away”.

Better surely to normalise the act of one-off donation, along the lines of blood donorship (where they don’t tell you – and please don’t ask – how many already donated blood samples need to be excluded from the transfusion bank).

That way the largest possible number of men could begin to imagine it was normal, your duty even, to donate, without becoming alarmed as to the potential consequences or commitment.

Once you’ve got your contingent of suitable donors in through the door, you could then explain what they’ve got themselves, and their “guys”, into.

It’s the good old “Availability Heuristic” at work – with added “Recency Effect”!

Using US figures (where more skydiving happens than in every other country combined) there’s 0.0007% chance of dying from a skydive, compared to a 0.0167% chance of dying in a car accident (based on driving 10,000 miles).

Put another way you are about 24 times more likely to die in a car accident than in a skydiving one.

It looks even better when you compare it to other things people consider perfectly safe and normal like riding a bicycle in an urban environment (insane) or any form of equestrianism (probably the single most dangerous activity of all).

Skydiving is all about safety, not about danger.

All about mitigating risks with training and technology.

And the average number of skydiving fatalities per year is almost half of what it used to be in the 1970s.

But these statistic apologists are missing the point too.

We do do it for fun, no question about it.

So what is that fun precisely?

My perspective is that almost all participants in almost every sport benefit from a physiological thrill provided by endorphins.

People who do risky things get the additional benefit from a blast of adrenaline – the body’s drug of last resort.

It’s adrenaline that has helped mothers lift cars that are crushing their children.

It’s adrenaline that explains how indifferent runners can outrun athletes, when they’re in danger.

It helps you focus your mental and physical resources in times of need. And it’s strong stuff.

I skydive to relax.

When I lie on a beach, I worry about all things I ought to be doing at home and at work.

When I read a book, even when I’m really enjoying it, I feel a bit guilty I’m not ‘getting on with something”

When I’m jumping out of a ‘plane I’m thinking about how to get back on the ground in one piece.

And if I do that five or six times a day, I end up physically exhausted with a mind that feels like it’s been down the boot-sale and unloaded a whole attic full of neural junk.

And I’m properly relaxed.

I know I get some of the same benefits from skiing and scuba-diving.

The special appeal of skydiving, to me, is the combination of max-adrenaline (that comes from the high-stakes involved) and high levels of control (equipment, training, focus) that give me the confidence to enjoy it.

As I think of the poor Prime Minister “chillaxing” with his Angry Birds, I wonder whether he wouldn’t be better off thrillaxing with us?